The city was declared a disaster area and its recreation center was converted into a shelter. Dallas County sheriff's deputies responded to reports of looting, and Sheriff Lupe Valdez toured the area, a spokeswoman said.

A curfew was imposed overnight and part of the city was blockaded, Knight said.

"The public's safety is paramount," he said.

About 30 miles northwest, a tornado tore through Arlington, home of the Texas Rangers, causing significant damage to homes and businesses, including a nursing home. That city's mayor signed a disaster declaration.

To the southwest in Burleson, Spinks Airport manager Aaron Barth also spotted a tornado approaching shortly before 1 p.m.

"The rotation was present there and slowly descended down, touched down for about 15 seconds one to two miles east," he said.

As he watched, the twister veered away from the airport, causing no injuries or damage, Barth said.

Elsewhere, tornadoes tossed tractor-trailers, ripped the roofs off houses, churned walls into planks and strewed them across suburban streets.

Emergency responders were still trying to tally damages late Tuesday.

"I can't give damage assessment numbers because the storm system is so broad-based; it's covering such a wide swath of the region," said Maria Anita, a Dallas County spokeswoman.

At least 12,000 people were without power in Fort Worth after the tornadoes hit, a Tarrant County spokesman said.

American Airlines canceled nearly all departures from its hub at Dallas-Fort Worth International Airport on Tuesday evening and diverted others to different airports, said Fort Worth-based American spokesman Tim Smith.

An airport spokesman, David Magana, said 405 flights were canceled and 110 planes damaged by hail. It wasn't clear how many belonged to American, which along with American Eagle had pulled 101 planes out of service for damage inspections.

At Dallas Love Field, passengers were forced to evacuate and take temporary shelter during the storm, and Southwest Airlines canceled more than 45 flights.